T 1.10-1.14 Flashcards
Tectonic context of the Philippines
- situated on complex multiple player boundary in ring of fire
- 2 major destructive margins joined by conservative margin
- has 37 volcanoes with 18 active ones
- 12 destructive earthquakes recorded in last 40 years
- eastern and northern coasts face the Pacific Ocean
- events can leave steep rugged slopes and poor vegetation
Hydro-meteorological context of Philippines
- tropical monsoonal climate brings rain bearing winds
- lies within SE Asia’s typhoon belt
- average of 20 typhoons hit the country, 7-10 expected to be destructive
- high risk of storm surges, floods and landslides
- El Niño brings periodic drought like in 1998
Development context of Philippines
- rapidly developing lower middle income country with large population (101 million with 1.72% annual growth)
- rapid urbanisation has led to large unplanned informal settlements and high pop. densities
- 25% of population live in poverty
- 50% of rural population like in poverty
- high levels of deforestation and widespread corruption
Facts and figures about Philippines country
- ranked 3rd in world risk index 2016
- eight the ten most risky cities from natural hazards in here
- 74% of population exposed to two or more hazards
- called a multiple hazard zone
- 555 major hazard events experienced between 1960-2015
Negative impacts of previous hazard events in Philippines
- tectonic events leave steep slopes, rugged land and poor vegetation cover
- extreme weather events/ heavy rainfall, eg La Niña saturate the soil and trigger mud/landslides particularly if the vegetation has been removed
- heavy rain with volcanic ash, creating large lahars that kill lellle eg, typhoon Yüna in 1991
- eruptions release water and the plume creates static charges that creates lighting and thunderstorms
What happened in 1991 in the Philippines?
- mount pinatubo and typhoo Yüna
- June 15th 1991, second largest eruption of 20th century (VEI 6) generated large pyroclastic flows and clouds of volcanic ash
- event coincided with typhoon Yüna with winds of up to 120mph
- rainfall mixed with volcanic ash = devastating lahars that swept through towns
Stats of 1991 disaster Philippines
- 847 reported to have died
- 73k houses damaged by heavy wet ash
- economic impact estimated at 211 million
- powerful eruption ejected significant quantities of aerosols and dust into the stratosphere
What happened in 2006 in the Philippines?
- Mount Mahon and typhoon Durian
- active strati volcano erupts frequently (50+ in past 500)
- activity and perfect shape is major tourist attraction
- quiet and effusive eruptions throughout 2006
- typhoon Durian caressed volcanoes path in November
- rainfall, flooding, mudflows and lahars
Stats of 2006 Philippines disaster
- 457mm rainfall = flooding in legazpi city (main port)
- Rainfall mixed with ash debris an debris to create mudflows and lahars that buried farms and villages, killing 1250+
Catania facts and figures
- east coast of Sicily on the base of mount Etna
- last major eruption in 2006
- benefits from fertile soils and vineyards
- airspace impact can close Catania airport
physical factors that affect resppmse
- geographical accessibility of location
- type of hazard (scale, impact magnitude, frequency)
- topography of the region
- climate
Human factors that affect response
- number of people involved
- degree of community preparedness
- technological resources
- education and training
- infrastructure
- economic wealth
Why does Sicily struggle to cope?
- each eruption is difficult - crust fracture points in different places, lava viscosity and gas eruptions vary considerably
- unexpected timings of minor eruptions
- computer modelling only as good as data that goes in
- municipality of government - politics of deciding who has responsibility
Vulnerable infrastructure in Sicily
- sapienza ski refuge with cable car and ski lifts, together with northern ski resort
- the round etna railway
- Catania airport
Vulnerable communities in Sicily
- rural - vineyards, olive groves, Mediterranean agriculture on rich volcanic soil
- main roads around the edge of the island to Palermo and Messina docks
Summer tourism in Sicily
- ash, like cement is water proof so very difficult to remove
- built Earth barriers/ explosives to disrupt and redirect lava
National governance in Sicily
- financial assistance from the Italian government is often needed - perhaps 5-6 million to account for losses in tourism and agriculture
Scientists in Sicily
Use a multi component gas analyser system
Regional politics in Sicily
- 10 municipalities meet at one point, making it extremely difficult to decide who is responsible for what
What does the hazard management cycle consist of?
Preparation
Response
Recovery
Mitigation
What’s preparation?
- strategies that focus on ensuring that emergency services and people at risk are aware of how to react during an event, occurs after the hazard response
What’s response stage?
Focused on the immediate needs of the population, such as the protection of life and property and includes firefighting, emergency services, evacuation, etc
What is the recovery stage?
- recovery is the equivalent to long term responses and is where the city authorities focus on clean up and rebuilding, can take months or even years
What’s the mitigation stage?
- involves authorities looking at the impact of the hazard and rebuilding in a better way to reduce similar impacts from a future hazard
describe the Himalayas
- Tethys ocean between India and Asia close 50 million years ago(was subducted)
- fold mountains thrust upwards with continental collision - collision boundary
- continue to be uplifted at rate of roughly 2cm a year
what are L waves?
Love waves:
- slowest but most destructive wave only move at surface
- they have the largest amplitude and shake the ground from side to side as wave travels forward
what are P waves?
Primary waves
- have a shirt wavelength and travel fast through both solid rock and liquid
- waves push and pull in the direction of travel to create compressional and extensional zones
what are S waves?
- longer wavelength and movement is perpendicular to direction of travel
- slower than P waves and only moves through solid rock - not liquid!
Effects of wave:
tsunamis landslides liquefaction aftershocks fires (ruptured gas/electricity lines) spread of disease
what are the primary effects of a wave?
those that happen as a direct result of earthquakes such as:
- ground shaking
- crustal fracturing - energy released caused crust to crack and land to be displaced vertically
what are the secondary effects of a wave?
those that are indirectly caused by earthquakes, often causing much more damage than initial shaking;
- landslides
- liquefaction
how are landslides caused?
shaking places rock slopes under increased stress which could lead to failure
how is liquefaction caused?
surface rocks lose strength in violent shaking and become more liquid than solid, thus losing its ability to support building foundations and cars
what are aftershocks?
- often smaller earthquakes can continue to occur whilst the fault settles down or readjusts to the initial release of strain
- can significantly hamper response and recovery
- 5.3 magnitude in Christchurch 2011
how to predict earthquake waves?
- very difficult to price accurately, foreshocks are being looked at to provide precursors for a potential earthquake
- animal behaviour could also be a sign
- p waves can be useful to trigger early warning systems which aids immediate responses
inequalities to access of housing in Nepal
- nepalese share inherited property, so very tall, thin houses are split vertically
- 5 million people crammed into shoddy concrete buildings, narrow alleys and hillside in he capital Kathmandu
inequalities to access of education in Nepal
- access to schools in mountain environment is hard - 6000 schools destroyed
- illiteracy rates - 71% female, 44% male
inequalities to access of healthcare in Nepal:
- close contact causes disease and infection spreading, particularly in shelters.
- rural areas - hospital is a 3hour walk through mountains
- medicines require payment
inequalities to access of equal income in Nepal:
- caste structure creates division
- Dalits living in stone/mud houses which collapse due to quake tremors
- 80% of concrete dwellings, occupied by higher castes state intact
- more debris reduces food supply (mix and contamination)
Nepal earthquake 2015 facts and figures
- 9k dead, 22k injured
- magnitude 7.8
- avalanche on Mount Everest kiled 21
- huge damages to UNESCO world heritage sites
Earthquake in Bam description
- 5.26 am
- cold weather
- arabian and eurasian plates collided
Bam facts and figures
- relatively low magnitude of 6.6
- 2003
- 26k+ people died
- focus depth of only 7km
what is governance?
- ability of an organisation or group of people to plan or manage hazard events effectively
- eg, local governments might organise evacuation strategies
- national gov might finance emergency care, etc
governance factors in Bam
- old mud brick buildings key to tourism (2400 yrs old)
- Iranian building code had not been effectively reinforced
- heavy roofs in buildings
- wooden structures were pre weakened by termite damage
- 3 main hospitals all destroyed in the EQ
- infrastructure blocked by rubble - harder to access
geographic factors in bam
- bam is isolated - 190km away from nearest town
- desert environment provides resources for mud houses
- located on complex tectonic setting, prone to faulting and thrusting of the crust
- cold winter temperature
- seismic waves caused significant ground shaking
Inequality is not inevitable
• The tectonic setting determines the nature of the hazard, e.g. 90% of tsunamis are in the Pacific Ocean
• Governance can reduce vulnerability, e.g. San Francisco has strict building codes
• Education can also reduce vulnerability, e.g. Japan
Inequality is inevitable
• Some communities are isolated, e.g. Nepal
• Socio-economic characteristics are vital – e.g. quality of housing,
• Not everyone can access education, and governance does not always govern everyone, (structural inequality)
• Older and younger groups will also be medically more vulnerably
